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    Re: Bias and cocked hats
    From: Peter Fogg
    Date: 2007 Apr 19, 13:09 +1000


     dw wrote:
     
    Having asked:
    > Is this assumption of only random errors reliable? What happens if some
    > systematic error is also involved?
     
    Dan Walden responded:
    It's again a reasonable assumption
     
    Leaving me a little puzzled. What's a reasonable assumption? That there is a total absence of systematic error? How can this assumption be supported?

    If by systematic error you mean something other than a constant bias,
     
    As to what I mean by systematic error, there have been a few postings recently on this topic.

    I suppose there could be an error proportional to altitude for
    example.  
     
    For example. There could also easily be a consistent error in time, whether due to a transcription error between the instrument and the recorded moment, or instrument error, or misapplied error correction, and so on.
     
    Remember that Alexandre over a few years now has complained about a suspected systematic error involving his Russian sextant.
     
    There also could be a consistent error due to misreading of the sextant scale, as well as instrument error or damage.

    But for measurements between 30 and 60 or so I would think
    the chance of such an error being significant is unlikely.  
     
    30 and 60 what? And again, how can you simply wave away systematic error as unlikely, regardless of its size?

     

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